Posts Tagged NB-6L

Arduino Battery Capacity Tester

  NOTE! This Arduino Battery Capacity Tester has been updated!
See the new, more general, improved and still simplified version of the
New Battery Capacity Tester here!


Arduino Battery Capacity Tester CircuitTo automate the testing of camera batteries and to make the tests repeatable I came up with a small circuit controlled by a Arduino microcontroller  – you can see the battery capacity tester circuit on the left. (If anyone is interested I can put up the Arduino program that controls it.) I have used this on my tests of camera batteries – check them out!

Someone was! 🙂  (Interested in the Arduino program!) Link at the bottom of this post! The program outputs measurements to the serial monitor.  I just copy it from there to Excel and do the calculations and graphics in Excel.

After some consideration about the measurement process I decided to try to approximate the real world picture-taking – but I also wanted a repeatable and reasonable easy and quick way of comparing different batteries. The circuit I decided on can handle the three most common batteries: 1.2 V NiMh, 3.7  and 7.4 V Li-ion by changing the load resistor. I wanted the load to mimic the actual taking of pictures by applying the load for a number of shorter times – like taking pictures.

For the 3.7 V Li-ion batteries on test here I decided that, as the battery according to Canon should give about 300 pictures, I would apply the load in around 300 short intervals. That ideally translated to a 5.2 ohm resistor giving around 500 mA load for 16 seconds each. Settled for a more standard resistor of 5.6 ohm. The load in this case is around 2.5 watts so use an appropriate resistor – with higher rating unless you want it to get very hot! 🙂  I also decided to let the battery “catch its breath”  for 16 seconds between each “picture” – again mimicking (very oversimplified) the real world behaviour while keeping the testing time down. Initially I wanted to follow a “real” standard like the CIPA one – but it was much to complicated for me and would involve far too much manual work. More to read about battery measurement in the CIPA document – but be warned it is very technical!

PEPs This 16 second 5.6 ohm load followed by a 16 second rest period just had to have a name so I called it Photoman Equivalent Picture samples (PEPs) – cool eh? 😉 NOTE that this is not real pictures taken but gives a good enough approximation – especially for comparing camera batteries! . The circuit takes into account the resistance of the MOSFET transistor used – just below 0.4 ohm – but it lowers the load a little bit. Running through the whole test takes about 3 hours per battery. Cut off voltage is 3.0 V for Li-ion batteries so that is where I stopped the tests. (This goes well with my Canon S95 that signals empty battery at that voltage.)

mAh My testing method also gives the capacity in mAh under the above “simulated real world picture-taking” conditions. Note that under other (“laboratory”) conditions these batteries can give other mAh capacities – but as I do it the same way in all my tests you can compare the results between the batteries that I test.

Here is a link to the Arduino program: BatteryCapacityTester

NOTE: Right click on the link and select “Save target as…” Due to limitations with WordPress this Arduino source code file has been given the extension “.doc”. After saving this to your disk rename the extension to “.ino”.

Also note that a NEW Battery Capacity Tester with a more general focus for all kinds of batteries can be found here!

As usual if anything goes wrong or gets broken by using this information I am sorry – but all the decisions are yours!

Photoman Signature

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Canon NB-6L Compatible Battery

This is a test and comparison of the electrical characteristics of three NB-6L batteries for Canon PowerShot S95 (original and compatibles).

After a very long wait (25 days for the shipping) for batteries the two NB-6L compatibles finally arrived from Deal Extreme. Priced at just 3.6 EUR/$5 each including shipping they are really a very cheap alternative to the original which are 15 times as expensive here in Sweden!

I also ordered one NB-6L compatible battery from an eBay shop called Broadbattery. Depending on where you live and how lucky you are in the bidding it can – at the moment – cost as little as $ 0.90 including shipping! I got mine for $2 + $2 shipping (2.7 EUR/$4). It arrived much quicker after “just” 12 days!

Having bought a set of compatible batteries that has worked very well – so far – for my Canon EOS 550D (Read my test of LP-E8 compatible battery here!) I decided to go about it the same way – testing and comparing the batteries as far as I could – before putting them in the camera!

The Deal Extreme batteries came very well packed in separate blister packs with a lot of “quality inspiring” text: 100% Compatible Original, Intelligence Protection, New Technology, Longrun Lithium, NO Memory Effect and IC Control. (Second one sure is scary! 😉 )
The Broadbattery one had less fancy packaging but was still well packed in a padded envelope with an extra plastic “bubble” bag  around it! All batteries arrived in perfect condition!

I must admit that I always feel a slight worry 😦 about these compatible batteries – so I try to be as “sure” as I can before I give them the GO! I feel that there are two different areas which to consider: First of all is whether the battery is safe – voltage and current wise – that is if all voltages are reasonably close to the original. This I can measure! Secondly, most (all?) Li-ion batteries contain some sort of protection circuitry for short-circuit, overloading and over charging – and this I will not be able to access and therefore can not comment on!

NOTE! This test of compatible batteries just shows the results from the samples that I got and that I give NO GUARANTEE that any batteries bought by you will work as the ones I got! Any tests that you make are your own responsibility!

My Canon PowerShot S95 seems to really eat battery power! So having a pair of extra batteries is something I would recommend to anyone – especially at these ridiculously low prices! Also having extra high capacity is quite tempting…

The original Canon NB-6L is specified as 3.7 V, 1000 mAh (min 940 mAh) and the NB-6L compatibles are specified as Broadbattery 1600(!) mAh and Deal Extreme 850 mAh so if these specifications are to be trusted – the compatible batteries should give around 60% more or 15% fewer shots.

A funny observation I have made with the original is that it seems to “recuperate” to some extent after the camera has switched itself off. Just a few seconds later I can take maybe 5 more pictures – and I can repeat this 2-3 times… One more observation – the original battery goes from full via 2 stripes to empty very quickly – it is not as if the stripes indicate some sort of proportionality….

As you can see from the picture the Deal Extreme compatible is of a completely different design from the original Canon and Broadbattery ones! But size measurements are within 0.1 mm of each other – so size wise there should be no problem! The weight differs very slightly – the original weighing in at 19 grammes and the compatibles at 18 and 19 grammes. All have a good, light but very solid feel to them!

After charging all three batteries I set about to measure them under different loads – before even considering to put them in my Canon S95. Charging proceeded similarly for all three of the batteries!
NOTE! After getting a “normal” response  from all three batteries in the capacity test I redid the following Load tests!

The different measurements that I did show VERY SIMILAR results from the original and all of the compatibles! They are so close to the original that it is impossible to pick out the different curves in the diagram! They are like identical twins – measurement wise! This at least convinces me that there should be very little risk in putting the them in the S95! 

After brooding for a few minutes – first thinking about what could go wrong I then thought about the similarities. All of them the exact same size – should fit well in the camera! They had fit well in the charger – but that is not such a tight fit. Then – as far as I could measure – the voltages under load were the exactly same – so that should pose no problem! The weights were also very close! The text on the package about “100% Compatible” seems to be correct – according to my measurements!

The question that is left is that about the protection circuitry – should one trust or laugh at the text about this: “Intelligence Protection” and “IC Control”. It sounds as if it has the relevant circuitry … Bad english can be forgiven – but to find out if these statements are true I would have to open the batteries and this I will not do!

Finally I put the Deal Extreme battery in the camera and switched it on … and it workedI am very glad to say! 🙂 The fit was perfect – as it should be with such close size! Then I repeated it with the Broadbattery – and again it worked – I am again very glad to say! 🙂

For capacity measurements of these batteries look HERE!

Now I have all the NB-6L batteries that I need for my Canon PowerShot S95 – for a very low price!

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